Aerosol apparatus



Feb. 22, 1966 J. RAMIS 3,236,458

AEROSOL APPARATUS Filed Feb. 14, 1963 3 Sheets-Sheet 1 dear; Pam/s IN VEN TOR.

BY W

Attorney Feb. 22, 1966 J. RAMIS 3,236,458

AEROSOL APPARATUS Filed Feb. 14, 1963 3 Sheets-Sheet 2 Attorney Feb. 22,1966 .s. RAMIS AEROSOL APPARATUS 3 Sheets-Sheet 5 Filed Feb. 14, 1963Jean Ramls IN VE N TOR.

Attorney NNNN I i N N i N N United States Patent 3,236,458 AEROSOLAPPARATUS Jean Ramis, Marly-le-Roi, Seine-et-Oise, France Filed Feb. 14,1963, Ser. No. 258,440 Claims priority, application France, Feb. 23,1962, 888,964 5 Claims. (Cl. 239-338) This invention relates toapparatus for the production of aerosols and more particularly toapparatus which will provide an aerosol dispersion in which theparticles are of very uniform size and within required limitations ofsize.

Apparatus for the production of aerosols usually comprise a containercharged with a propellant liquid and a substance intended to bedischarged in aerosol condition, the container being provided with atriggerable discharge valve and nozzle connected to a tube passing downthe vessel to terminate just short of its base. The vapor pressure abovethe liquid in the container thus forces it towards the valve and jetnozzle so that, on release of the valve the liquid rises to the valvewhere it vaporizes and is discharged.

In the case where the aerosol is required for therapeutic purposes inproviding an inhalant, for example, the common form of aerosol-producingapparatus is not entirely satisfactory since the particles of the formedaerosol are not wholly within the desired limits of size. In fact, forsuch purposes it is desired that the particles of the therapeutic agentshould be between 0.5 and 5 microns in size since particles above 5microns may not reach the air-cells of the lungs while particles below0.5 micron may fail to be deposited therein.

It is an object of the present invention to provide improved apparatusfor the production of aerosols, particularly aerosols of therapeuticsubstances, which is adapted to yield aerosols whose particles are ofvery uniform size and substantially within the foregoing limits andwhich is of economical and compact design.

According to the present invention there is provided apparatus for theproduction of an aerosol dispersion which comprises a container for apropellant liquid and a substance which it is desired to discharge inaerosol condition, a triggerable discharge valve and nozzle unit forsaid container adapted, on actuation, to discharge the contents from thecontainer in the form of a directional jet, and a tube extendingforwardly of the nozzle opening substantially coaxially of the dischargejet, this tube being at least partially open at its rearward end (withrespect to the nozzle) and providing a partial barrier to the freeforward movement of the discharge jet.

In one form of the invention, the partial barrier or hindrance isprovided in the form of one or more baflie plates disposed transverselyto the axis of the tube and having finely polished surfaces facingtowards the jet openings Such plates form a bafile or labyrinth whichprevents the particles of the discharge jet from leaving the end of thetube in a straight line.

In this embodiment of the invention, the coarse particles of liquidemitted by the valve and traveling at a speed which is higher than thatof the small particles strike the plates and break up into smallerparticles which pass around the said plates at reduced speed, so thatthe discharged material leaves the end of the tube in the form of ahomogeneous jet at low speed.

In another embodiment of the invention, the tube does not contain anyinternal solid bafile plates but is so dimensioned that the mass of aircontained in the tube itself impedes the forward flow of the stream andserves as a barrier. Specifically, according to this embodiment thedischarge aperture has a diameter of 0.1 to 0.3 mm., the

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inside diameter of the tube is 10 to 40 mm. and preferably 18 to 30 mm.and its length is between three and ten times its diameter, preferablyfive to seven times.

With this embodiment it has experimentally been found that the jetemerging from the tube is again, as in the first case, a homogeneous jetwhose diameter is equal to that of the tube and whose speed issubstantially uniform across the crosssection of the tube.

A complete explanation of the behavior of the apparatus according tothis second embodiment of the invention cannot be given with certainty,particularly because vaporization of the liquefied propellant gasresults in thermodynamic effects. However, it is believed that theapparatus behaves as an ejector: by the transfer of momentum the jetentrains air inside the tube, but this transfer implies impacts,particularly between particles already dispersed in the air andparticles contained in the jet, and this breaks up these particles, sothat the composition of the jet leaving the tube is rendered homogeneousand the speed of the particles is substantially uniform across the wholecross-section of the emergent jet.- In other words, the physicalobstacle in the form of bafiies in the first form of the invention isreplaced by the obstacle comprising the flow resistance of the aircontained in the open tube if this tube is sufiiciently long.

In specific forms of apparatus, according to the invention, where a tubewithout physical baflles is employed, the tube may be in twotelescopically interfitting parts and be collapsible to form a housingfor the container. In that case the tube part forming the inner memberof the telescopic assembly may contain a head having a radial ductleading into a wall of this inner tube part, the outlet tube of thecontainer being connected to that duct. Further, the tube partcontaining the head may be crowned by a cap rotatable through a limitedangle to pass from a position in which the cap shuts off aperturesformed in an end of this tube part, thereby blocking the inlet apertureto the radial duct in the head, and a position in which it opens theseapertures.

Further, in all forms of the apparatus the nozzle unit may comprise achamber in which the liquid to be discharged is rotated as it arrivestangentially to the chamber, the chamber being formed by twofrusto-conical cavities having adjacent bases of the same diameter, oneof these cavities being extended to form a short cylindrical outletaperture.

The foregoing specific embodiments of the invention are referred to inmore detail in the following description and will be described withreference to the accompanying drawing wherein:

FIG. 1 is a diagrammatic sectional View of one embodiment of theinvention;

FIG. 2 is a diagrammatic sectional view of another embodiment of theinvention;

FIG. 3 is a sectional view of a specific construction, according to theinvention, in an inoperative position;

FIGS. 4a and 4b are sections on line IV-IV in FIG. 3, showing part ofthe apparatus of FIG. 3 in two different positions;

FIG. 5 is a sectional view of the device of FIG. 3, in an operativeposition;

FIG. 6 shows the apparatus of FIG. 3 in perspective; and

FIG. 7 is a perspective exploded view of the spray nozzle.

Throughout the several views, similar parts are similarly numbered.

In FIGS. 1 and 2, the containers 1 include tubes 2 leading to nozzleopenings 5 through a conventional valve system (not shown) which iscontained in the head 3 and can be operated by pressure exerted manuallyon the side lugs 4 of the head. Preferably, to obtain good spraying atthe nozzle, the nozzle opening assembly is of the type creating aturbulent discharge jet; an embodiment of such an assembly is describedhereinbelow. The valve used may be an ordinary valve or a metering valveof known type.

The pressure-resistant containers 1 contain a liquid 6 which, forexample, includes dichloro-difluoro-methane, this propellant being knowncommercially as Freon 12, in which an active product is dissolved orkept in a homogeneous emulsional suspension.

The vapor pressure of dichloro-difiuoro methane at a temperature of 20C. is approximately atmospheres. To obtain a more powerful discharge jetat the opening 5, an inert gas insoluble in the liquid 6, for examplenitrogen, may be added to the gas atmosphere of the container.

In the embodiment shown in FIG. 1, a tube 8 is attached to the head 3through the agency of a base 7 which is formed with air apertures 7a.This tube forms an expansion chamber around the jet opening 5 of thehead 3. On the side opposite opening 5 this tube is partially closed bya ring shaped plate 9 and a discshaped plate 10, which is connected tothe annular plate 9 by supports 11. The disc is offset towards theinterior of the chamber with respect to the ring 9 and its diameter issubstantially equal to that of the ring opening so that a stream of gaspassing through the tube 8 cannot travel to the end of the tube in astraight line.

Thus, the particles leaving the orifice 5 are projected against theinner surface of the disc 10 where they break up. Moreover, turbulentmovement is set up within the discharge jet and this results inhomogenization of the discharge jet so that, as shown by the arrows, ahomogeneous mixture of fine particles of gas and air leaves through thegap between the annular plate 9 and the disc plate 10 and escapes fromthe tube at a slow speed in the form of a homogeneous mist.

Preferably, the disc 10 has a slightly larger diameter than the sectiona of the conical discharge jet emerging from the opening 5 at the pointwhere this jet makes contact with the disc. Moreover, the disc ispreferably thickened at its center as shown to present a convex surfaceto the discharge jet, and is finely polished. In this way the risk ofparticles from the discharge jet being retained on the face of the discmay be minimized.

In the embodiment shown in FIG. 2, a tube 12 surrounding the streamleaving the nozzle opening 5 does not contain any solid internalobstacle. For an orifice of a diameter of about 0.2 mm., the diameter Dof the tube is between 10 and 40 mm., and, preferably, for best results,between 18 and 30 mm. A diameter of 20 to 28 mm. has been found to beparticularly suitable for most known therapeutic products.

Since the end of the tube 12 connected to the head 3 is very close tothe orifice 5 the length L of this tube must be between 3 to 10 timesthe diameter D. However, lengths between 5 and 7 diameters give the bestresults. A relatively slow and homogeneous discharge jet, the particlesof which are of sizes within the optimum limits, leaves at a uniformspeed over the entire section of the tube from the aperture 12b as shownby the arrows.

The dimensions of the tube which is disposed around the discharge jet toprovide the results indicated above are such that this tube is alsosuitable for use as a housing for the liquid container. Moreover, sincethis tube is relatively long, it may be advantageous to make it in atelescopic form so that it can be collapsed to smaller overalldimensions. 1

FIGS. 3 to 7 show such an embodiment of the invention. The tube isformed by two elements 15 and 16 sliding one inside the other. To limittheir relative displacement, the outer tube 15 has an internalperipheral bulge 15a and the inner tube 16 has an external peripheral 4.bulge 16a. These bulges abut (FIG. 5) when the syste is at maximumextension.

The inner tube 16 is closed by an end 18 formed with a central aperture21 and peripheral apertures, one aperture 21) being in the form of asector while the other aperatures 19 are circular (FIGS. 4a and 4b).

The extremity of the tube 16 carrying the end 18 is covered by a cap 22of molded flexible material having the inside of its fiat wall formedwith a central stud 23 which is received with a press fit in theaperture 21 so as to fix the cap in place; this flat wall also hasapertures 24- of the same arrangement and distribution as the apertures19 and 20 in the end of the tube 16 and carries on its inner surface alug 25 which engages in the aperture 29. Thus the cap 22 can turn on thetube 16 through an angle limited by abutment of the lug 25 against thetwo radial edges of the aperture 20, thus enabling the apertures 19 and21} either to register with the apertures 24 or to be blocked by thesolid parts of the flat wall of the cap when the latter is in a positionof closure. A diametrically extending insert of head 27 is disposedwithin the tube 16 near the end 18 thereof.

The head is of cylindrical shape and is fitted by its ends in twodiametrically opposite bores 28 and 29 of the tube 16 and is preventedfrom turning by a lug 30 engaging between projections 31 on the innerWall of the tube 16.

On the inside, the head 27 contains a duct 32 discharging through aright-angle deflecting aperture 33 into a shouldered cup 34. ReceivedWithin cups 34, and bearing against its shoulder, is a stack formed bythree elements of a nozzle unit shown in FIG. 7, namely a filter 35, avortex-forming cylinder 36 and a plate 37 formed with a smallvaporization aperture 38. The vortex cylinder 36 has a rear cavity 39communicating through two wide opposite recesses 49 with the frontsurface of the cylinder. Slots 41 are formed on this front surface andlead tangentially in the same direction to the edge of the centralfrusto-conical cavity 42 of the front surface of the hollow cylinder 36.The cavity 42 co-operates with the rear frusto-conical end 43 of theaperture 38 (the two frustocone bases having the same diameter) to forma small chamber in which the liquid arriving through the filter 35, thecavity 39 and the channels 4-0 and 41 flows turbulently before leavingin the form of a fast conical jet through the aperture 38. It is wellknown that if this liquid is a liquefied prop-ellent gas associated witha liquid product for spraying, such as arrangement already gives a veryfine spray.

The liquid to be sprayed is contained in a cylindrical receptacle 44,whose outer diameter corresponds to the inside diameter of the tube 16so that it can be housed therein (FIG. 3). This container is providedwith a valve (not shown) disposed in the fixing a mounting flange 45,this valve terminating in a hollow stem 46. The valve in flange 45 ispreferably a conventional metering valve so that a limited quantity ofliquid leaves the end of the valve stem 46 when this stem is pushedtowards the interior of the container 44.

In the inoperative position (FIG. 3), the flange 45 engages a number offine ribs 47 formed in the inner wall of the inner tube 16 so that thecontainer forced inside the tube 16 is held there by resilient pressure.Excessive penetration of the container into the tube 16 is prevented bya shoulder 48 which meets the endsof tubes 15 and 16 and which is of thesame diameter as the outside tube 15 so that the outside surface of thenested assembly (FIG. 3) is substantially continuous.

The peripheral wall or skirt of cap 22 has a hole 49 which registerswith the inlet to the duct 32 when the cap is in the position to openthe apertures 19.

Upon the withdrawal of container 44 from the interior of the tubes, itsoutlet tube 46 can be engaged in the head 27 when the holes 19 in theend 18 of the tube 16 are freed by suitable orientation of the cap 22with respect to that tube. In this position, the platform 50 of the capis diametrically opposite the container 44.

When the tube has been pulled so that the system formed by the two tubesis at its maximum length, a homogeneous mist of fine drops leaves thefree end of the tube 15 in the form of a vapor when pressure is appliedto the platform 50; if the tube 15 is allowed to remain telescoped ontothe tube 16 the spray is in the form of a fast moving non-homogeneouscloud.

In a practical construction of this apparatus the extended length of thetubes 15 and 16 was 13 centimeters and their inside diameter 2centimeters for an aperture 38 of diameter 0.18 mm.

I claim as my invention:

1. A device for producing an aerosol dispersion, comprising:

an elongated generally cylindrical tube open at one end and provided atits other end with a wall having at least one air hole and with alateral inlet aperture next to said wall;

a cap rotatably engaging said other end, said cap having at least oneport registering with said air hole in one rotary position, said caphaving another rotary position completely blocking the passage of airthrough said wall, said cap being further provided with a peripheralskirt extending across said inlet aperture, said skirt having an openingregistering with said inlet aperture in said one rotary position only;

a container for a substance to be dispensed along with a propellanttherefor, said container having a generally cylindrical body fittinginto the open end of said tube in an inoperative position, saidcontainer being provided with valve means including a tubular stemmatingly receivable in said inlet aperture upon alignment thereof withsaid opening in said one rotary position of said cap, said valve meansbeing triggerable for discharging a stream of particles from saidcontainer through said stem whereby said particles are radially injectedinto said tube by way of said inlet aperture;

and deflecting means for said stream disposed in said tube for directingsaid particles axially outwardly through said open end.

2. A device as defined in claim 1, further comprising co-operatingabutment means on said tube and said cap for enabling relative rotationthereof between limits respectively corresponding to said one and saidother rotary position.

3. A device for producing an aerosol dispersion, comprising:

an elongated generally cylindrical tube open at one end and provided atits other end with a wall having at least one air hole and with a pairof diametrically opposite lateral apertures next to said wall;

a cap rotatably engaging said other end, said cap having at least oneport registering with said air hole in one rotary position, said caphaving another rotary position completely blocking the passage of airthrough said wall, said cap being further provided with a peripheralskirt extending across said lateral apertures, said skirt having anopening registering with one of said apertures in said one rotaryposition l;

an insert extending diametrically through said tube at said other end,said insert having extremities received in said lateral apertures andbeing provided in one of said extremities with an inlet channelterminating at said one of said apertures for unblocking by said openingin said one rotary position of said cap, said inlet channelcommunicating with a central passage in said insert open toward said oneend of said tube;

a container for a substance to be dispensed along with a propellanttherefor, said container having a generally cylindrical body fittinginto the open end of said tube in an inoperative position, saidcontainer being provided with valve means including a tubular stemmatingly receivable in said inlet channel upon alignment thereof withsaid opening in said one rotary position of said cap, said valve meansbeing triggerable for discharging a stream of particles from saidcontainer through said stem whereby said particles are radially injectedinto said tube by way of said inlet channel;

and deflecting means for said stream disposed in said insert at thejunction of said channel with said passage for directing said particlesaxially outwardly through said open end.

4. A device as defined in claim 3 wherein said tube consists of an innersection and an outer section telescopically engaging each other, saidinner section being provided with said insert and said cap, said outersection being slidable on said inner section between an extendedposition remote from said cap and a retracted position adjacent saidcap, said body fitting into said inner section in the retracted positionof said outer section.

5. A device as defined in claim 4 wherein said body is formed with ashoulder remote from said stem engageable with the open end of said tubefor sealing same in said retracted position.

References Cited by the Examiner UNITED STATES PATENTS 2,890,697 6/1959Van Sickle 239-337 2,940,641 6/1960 Norris et al. 239-337 3,006,34010/1961 Meshberg 222394 3,012,555 12/1961 Mesh'berg 222-394 3,069,09712/1962 Cheney 239-338 3,101,904 8/1963 Prussin et al 239--339 3,104,0629/1963 Mahon 239338 3,107,670 10/1963 Silson et al 222394 FOREIGNPATENTS 868,785 5/1961 Great Britain.

M. HENSON WOOD, JR., Primary Examiner.

EVERETT W. KIRBY, Examiner.

1. A DEVICE FOR PRODUCING AN AEROSOL DISPERSION, COMPRISING: ANELONGATED GENERALLY CYLINDRICAL TUBE OPEN AT ONE END AND PROVIDED AT ITSOTHER END WITH A WALL HAVING AT LEAST ONE AIR HOLE AND WITH A LATERALINLET APERTURE NEXT TO SAID WALL; A CAP ROTATABLY ENGAGING SAID OTHEREND, SAID CAP HAVING AT LEAST ONE PORT REGISTERING WITH SAID AIR HOLE INONE ROTARY POSITION, SAID CAP HAVING ANOTHER ROTARY POSITION COMPLETELYBLOCKING THE PASSAGE OF AIR THROUGH SAID WALL, SAID CAP BEING FURTHERPROVIDED WITH A PERIPHERAL SKIRT EXTENDING ACROSS SAID INLET APERTURE,SAID SKIRT HAVING AN OPENING REGISTERING WITH SAID INLET APERTURE INSAID ONE ROTARY POSITION ONLY; A CONTAINER FOR A SUBSTANCE TO BEDISPENSED ALONG WITH A PROPELLANT THEREFOR, SAID CONTAINER HAVING AGENERALLY CYLINDRICAL BODY FITTING INTO THE OPEN END OF SAID TUBE IN ANINOPERATIVE POSITION, SAID CONTAINER BEING PROVIDED WITH VALVE MEANSINCLUDING A TUBULAR STEM MATINGLY RECEIVABLE IN SAID INLET APERTURE UPONALIGNMENT THEREOF WITH SAID OPENING IN SAID ONE ROTARY POSITION OF SAIDCAP, SAID VALVE MEANS BEING TRIGGERABLE FOR DISCHARGING A STREAM OFPARTICLES FROM SAID CONTAINER THROUGH SAID STEM WHEREBY SAID PARTICLESARE RADIALLY INJECTED INTO SAID TUBE BY WAY OF SAID INLET APERTURE; ANDDEFLECTING MEANS FOR SAID STREAM DISPOSED IN SAID TUBE FOR DIRECTINGSAID PARTICLES AXIALLY OUTWARDLY THROUGH SAID OPEN END.